Method and apparatus for temperature control in a refrigeration device

Abstract

A temperature control device including a temperature sensor which senses a temperature at a specified location within the refrigeration apparatus. The temperature control device has first flow valve that is operable to selectively increase or decrease the flow of refrigerant in response to the temperature sensed by the sensor. In addition, the device has a second flow valve that is operable to selectively increase or decrease hot gas flow in response to the temperature sensed by the sensor. The temperature control device also contains a controller which controls the above mentioned valves in response to the temperature sensed by the temperature sensor.

What is claimed is:  
     
       1. A temperature control device comprising: 
       a temperature sensor operable to sense a temperature at a certain location of said device;  
       a first flow valve operable to selectively increase or decrease refrigerant flow in a first flow path;  
       a second flow valve operable to selectively increase or decrease hot gas flow in a second flow path;  
       a primary controller that controls the first and second flow valves in response to the temperature sensed by the temperature sensor; and  
       a secondary controller operable to control the first and second flow valves in response to the temperature sensed by the temperature sensor.  
     
     
       2. The temperature control device according to  claim 1 , wherein the controller opens the first valve and closes the second valve when the sensed temperature is greater than a predetermined value. 
     
     
       3. The temperature control device according to  claim 1 , wherein the controller closes the first valve and opens the second valve when the sensed temperature is less than a predetermined value. 
     
     
       4. The temperature control device according to  claim 1 , wherein said first flow path comprises a compressor, a condenser and an evaporator. 
     
     
       5. The temperature control device according to  claim 4 , wherein said second flow path comprises said compressor and said evaporator. 
     
     
       6. The temperature control device according to  claim 1 , wherein said second flow path comprises a compressor and an evaporator. 
     
     
       7. The temperature control device according to  claim 6 , further comprising a capillary tube connected to said compressor wherein refrigerant from the compressor is cooled. 
     
     
       8. The temperature control device according to  claim 1 , wherein the primary controller is a primary thermostat. 
     
     
       9. The temperature control device according to  claim 1 , wherein the secondary controller is a secondary thermostat. 
     
     
       10. The temperature control device according to  claim 1 , wherein the secondary controller is activated to control the first and second flow valves when a malfunction occurs in the primary controller. 
     
     
       11. A system for controlling temperature, comprising: 
       means for sensing a temperature at a certain location of an incubation system;  
       means for increasing or decreasing refrigerant flow in a first flow path in response to the temperature sensed by the sensing means;  
       means for increasing or decreasing hot gas flow in a second flow path in response to the temperature sensed by the sensing means;  
       primary means for controlling the valves in response to the temperature sensed by the temperature sensing means; and  
       secondary means for controlling the valves in response to the temperature sensed by the temperature sensing means.  
     
     
       12. A system according to  claim 11 , wherein the primary means for controlling the valves opens a first flow valve and closes a second flow valve when the sensed temperature is greater than a predetermined valve. 
     
     
       13. A system according to  claim 11 , wherein the primary means for controlling: 
       regulates the air discharge temperature of said evaporator with a low pressure sensor by shutting down portions of the system and further  
       regulates the air discharge temperature of said evaporator with a high pressure sensor by shutting down portions of the system.  
     
     
       14. The system according to  claim 11 , wherein the secondary means for controlling the valves is activated when a malfunction occurs in the primary means for controlling the valves.